5 Whys: Cattle Shed Pump Failure

5 Whys:

Cattle Shed Pressure Pump Failure:

Purchased a “3.5HP 5 STAGE HIGH PRESSURE AUTO WATER PUMP Garden Tank Spa Pool” pump from ebay seller dreamrideronline with below features:

  • Tomahawk ™ USA
  • Mississipi Waterworx
  • Multistage Pressure Pump (5 Stage)
  • 3.5HP / 2500W
  • 5 Stainless Steel Impellers
  • 9900 Litres/ Hour
  • 165 Litres/ Minute
  • Huge 100m Head for Applications over 3 storeys
  • Self Priming
  • Stainless Steel Pump Housing, Shaft and Impellers
  • Alloy Motor Housing
  • Cermamic and Carbon Seals
  • Automatic Electronic On/Off Controller
  • Thermal Protection.
  • Pump has Failed on first run.

Why did the Pump Fail?

Pump motor was plugged into main electricity and due to incorrect wiring pulled more load amps than was available causing motor to not get past start winding and burnt start winding to ground. Motor now blows earth leakage immediately.

Why did motor states it as has “Thermal Protection”, wouldn’t this has caused the overload to blow allowing the pump to stop?

Upon inspection of Motor itself, there is no thermal or overload protection for brownout. However this may be in the controller unit that was not attached at the time.

Why was the pressure controller unit not attached?

Outlet was damaged due to over tightening of elbow connector. Plastic is very thin and a hand tighten was enough to snap the plastic.

Was this motor a good purchase under the circumstances?

In Hindsight No. The motor wattage is very high causing a High Start Amp load on the wiring. This means the normal 10Amp wiring was not good enough. While pipe connector was thin by comparison to Australia Made Pumps, this should have been taken into account when doing the install.

While this is a cheap pump, the catch is the Australian Pumps are 3 times as expensive. In theory this allows for 3 pumps to be purchased over the same lifetime. Of course it also allows for a high failure rate until the right equipment is found.

In this case, this pump was purchased due to lessons learnt on the previous purchase. The previous pump had plastic impellers that were quickly getting worn. So the next pump was found with stainless steel impellers. However only a large wattage pump was available. This caused the power issue.

Also with electricity costs, in hindsight, this may not be the best pump in the long run and may have cost more electricity than was saved in a cheap pump. The Cattle Shed does not require a pump with a high flow rate, it only fills up Chicken Sheds and Water troughs. With this in mind, the replacement pump needs to be only 1HP or less. Not 3HP.

Lessens Learned:

Don’t purchase high amp pumps from Ebay/China, the high amps may be hiding pump inefficiencies. It will also cause high load on wiring increasing failure rate of electrical equipment.

With the new knowledge what is required to pump water around the farm, an Australian Pump can be purchased with 2-3 Taps output. This might not as expensive and allow purchasing from an Australian Brand cost effective especially with power savings.

Leave a Reply